Conventional kitchen and bathroom sinks include a peripherally extending upper rim which, when installed, rests upon the top surface of the adjacent portion of the countertop. The sink is secured in place by a clamp construction which engages the underlying surface of the countertop to prevent the sink from being raised or moved sideways. Various types of mounting or clamping devices are known for securing sinks to countertops. Conventional sink clamp constructions, such as that shown in Canadian Patent No. 1,246,805 to Cappella which issued Dec. 20, 1988, typically consist of a weld bracket welded to the side of the sink and a movable clip arm member. The movable clip arm is in turn mechanically coupled to the bracket by a bolt mechanism which is threaded through an internally threaded aperture formed in the clip arm and which has a grooved end rotatably secured to the weld bracket. On rotation of the bolt, the bolt position remains constant relative to the sink. As a result, the clip arm moves axially as the bolt is turned by the threaded engagement between the bolt threads and internally threaded opening of the clip arm. Accordingly, the clip arm is moved vertically by rotating the bolt until the clip is brought into engagement with the underside of the countertop under compression to wedge the sink in place.
A disadvantage of the device disclosed in Canadian Patent No. 1,246,805 exists in that it requires the use of a customized bolt to movably couple the arm member to the weld bracket. The use of customized bolts increases the overall cost of the mounting device and hinders the simple substitution of longer or shorter bolts required to customize the mounting device for use with thicker or thinner countertops.
In addition to the increased costs associated with the manufacture of customized bolts, a further disadvantage with the Cappella mounting device exists in that as the bolt is tightened, the arm frequently turns together with the rotating bolt. This necessitates that two hands be used to operate the device when installing a sink. One hand is required to hold the clip arm in the correct orientation under the overhanging portion of the countertop and prevent its rotation out of alignment therewith, while the other hand turns the bolt. The necessity of using two hands to operate the mounting device may prevent an installer from securely holding the sink in the correct position during initial clamping. In addition, often the spacing between the rear edge of the sink bowl and the adjacent wall is insufficient to permit two-hand operation of the mounting device, with the result that as the clamp is tightened the clip arm member may rotate away from a position under the adjacent countertop overhang.
A further disadvantage of the Cappella sink mounting device exists in that as the clip arm is tightened and engages the underside of the countertop, the reaction forces at the end of the clip arm and the periphery of the screw head are concentrated on a very small area of contact with the side of the bowl. These reaction forces deform the side of the bowl, leaving an unsightly appearance.
As well, another disadvantage with the Cappella mounting device exists in that it may be used with only a limited number of sink designs. Because the weld brackets which are secured to the sides of the sink bowl often project radially therefrom up to 1 cm or more, they may interfere with the insertion of the sink bowl through the countertop hole. As such to ensure that the sink rim extends beyond the countertop hole, the Cappella mounting device may typically only be used on sinks which have a radially extending rim which extends at least 1.5 cm or more, and also the tolerance on the countertop hole must be tight to make it work.